Cost comparisons.... multi set up VMC vs mill/turn barfeed machine...

[InspirationTool]

This isn't an RFQ, but as it pertains to picking appropriate outsource companies, I'm putting it here.

Lately, it seems I'm designing alot of small parts that require at least 2 if not 3 or 4 operations (re-clamping) in a VMC.

Most of my parts that I'm thinking about are under 1 cubic inch and are brass with small threaded holes. The quantities tend to run 50 to 200, with prices running $2 to $10 each.

I'm wondering when it becomes worthwhile to have a bar feed mill/turn machine shop quote on the project. I figure those have to be a bit more difficult to set up and run than a VMC.

How many parts/setups do you need to be talking about before it is worth it to use a mill/turn machine?

Or are these machines fairly easy to program and cheap to run?

Can they barfeed rectangular stock?

Thanks!

-Jeff

[cdlenterprises]

It really depends on the complexity of the part and the time required to set it up on either machine. Throughput and labor also comes into play. First what do you consider to be a mill/turn machine? To me a two axis lathe with live tooling doesn't fall into this category. My idea of a mill/turn machine is a twin turret, twin spindle machine(basically over-sized swiss screw machines).

For example, I had a Nakamura WT-250 that I was responsible for a few years back. It was a twin turret(upper and lower) twin spindle(C-axis on both) with live tooling on all turret stations. It also had a Y-axis on the upper turret for cross milling. This machine was a bear to setup and program but it could make some SERIOUS (complex) parts. But while it would make these complex parts complete, the cycle time was 22 minutes per part.

So it really depends on what you're after. For low quantities in a job shop environment, usually the setup time and throughput of these machines doesn't justify the capabilities. But if unmanned operation is crucial (lights out mfg), they are certainly the way to go. They are also ideal for parts with tight geometrical call outs as every surface is machined at once and all datums are as accurate as the machine.

Bottom line is low quantity, short turnaround, it's pretty tough to beat a VMC (or HMC if you prefer) But if you could justify running the part on a Swiss type screw machine (taking size into consideration, naturally) then a mill/turn might be worth looking into.

My $.02

[big_mak]

Dude if its still 4 sided you may want to look at Horizontal shops, or guys who have a verticle with a 4th axis.

[billystein]

i use a haas tl25 with caxis,live tooling and sub chuck. it has the servo bar feed and tool probe.
i run 5 different pieces and change setups maybe once a week . the machine works ok. not to bad to setup. new progs take a day or so. old progs tak 2 to 4 hrs. depending how many tools you have to change.
the tooling is made so you can put 2 tools in each outside tool station. 1 for main chuck and one for sub chuck. there are only 12 tool stations and 6 are vdi holders. for live tooling.
the parts sound similar to what you are making and take about 3 minutes apeice.
i think it is an ok system but the price for the haas is around 200k.